✨(backend) add a flexible JSON field to store recording options

Using a JSON field allows iterating on recording data without running a new
migration each time additional options or metadata need to be tracked.

This comes with trade-offs, notably weaker data validation and less clarity on
which data can be stored alongside a recording.

In the long run, this JSON field can be refactored into dedicated columns once
the feature and data model have stabilized.

src/backend/core/models.py

@@ -577,6 +577,12 @@ class Recording(BaseModel):
         verbose_name=_("Recording mode"),
         help_text=_("Defines the mode of recording being called."),
     )
+    options = models.JSONField(
+        blank=True,
+        default=dict,
+        verbose_name=_("Recording options"),
+        help_text=_("Recording options"),
+    )
 
     class Meta:
         db_table = "meet_recording"